Structure for a semiconductor arrangement and a method of manufacturing a semiconductor arrangement

ABSTRACT

The invention relates to a structure for a semiconductor arrangement. A resist structure for supporting deposition of a solution containing a semiconductor is directly or through intervening layers coupled to a substrate. The resist structure comprises a depression ( 301 ) for depositing of the solution containing the semiconductor ( 309 ) and a trough ( 305 ) aligning at least part of an edge of the depression ( 309 ) and separated from the depression ( 309 ) by a protrusion ( 307 ). The trough ( 305 ) preferably surrounds the depression ( 309 ). The trough provides a pinning effect on the solution containing the semiconductor thereby improving the wettability and accordingly allowing for increased volume of semiconductor to be applied to a given area.

The invention relates to a structure for a semiconductor arrangement anda method of manufacturing a semiconductor arrangement and in particularto a semiconductor arrangement comprising a resist structure.

It has for many years been known to manufacture electronic semiconductorcomponents such as bipolar and field effect transistors usingsemiconductor materials such as silicon, germanium and gallium arsenide.Specifically, integrated circuits comprising many electronic componentsare manufactured by depositing conductive, semiconductive and insulatinglayers on a substrate.

In recent years, it has been realized that some organic materials, suchas for example Pentacene, Polythiophene, Polyfluorene,Polyphenylenevinylene, Triphenylamines may exhibit semiconductorproperties. Semiconductor components, arrangements and circuitscomprising organic semiconductors promise a number of advantages overtraditional semiconductor based structures including ease of processing,e.g. solution processing and their mechanical flexibility. Accordingly,much research has been undertaken in the field of organic semiconductorsand manufacturing of semiconductor components and circuits based onorganic semiconductors.

Also, in recent years, semiconductor based displays such as thin filmtransistor (TFT) displays have become increasingly widespread.Accordingly, much research has been undertaking in suitablemanufacturing methods for semiconductor structures and in particular formanufacturing of organic semiconductor structures or semiconductor baseddisplays.

One known method for manufacturing an organic semiconductor baseddisplay comprises applying the organic transistors of the display byspin coating. However the disadvantage of this technology is that auniform layer of semi conducting material is applied requiring aseparate patterning process. Therefore, a typically preferred method ofapplying the polymer is by use of printing processes, such as ink-jetprinting, whereby the semiconducting organic material may be directlyapplied in a pattern. In this way, the functional characteristics of thetransistor can be improved considerably.

To simplify the ink-jet printing process, i.e. to keep the ink-jetprinted liquid in the desired areas, the structure on which the liquidis printed typically comprises a resist structure, which prevents theprinted liquid to spread to unwanted areas.

Generally, the resist structures comprise wells or cavities that can befilled with liquid material by means of printing. FIG. 1 illustrates across section of a well of a resist structure in accordance with priorart. The resist structure 101 comprises a well 103 formed as adepression in the resist structure 101. A droplet 105 of a solutioncontaining the organic semiconductor has been dropped in the well 103.

In the situation where the angle of the liquid with the resist θ islarger than the advancing contact angle of the liquid with thesubstrate, wetting of the resist will occur until equilibrium isestablished, i.e. the angle of the liquid on the substrate is equal tothe advancing contact angle. FIG. 2 illustrates a cross section of awell of a resist structure in accordance with prior art. FIG. 2illustrates the same resist structure as in FIG. 1 but after theequilibrium has been reached. As can be seen a significant wetting ofthe resist has occurred. This results in a number of disadvantagesincluding poor control over the feature size (this makes it impossibleto make small features), poor registration (this may lead to undesiredleakage currents and parasitic capacitances).

The wetting of the resist depends on the contact angle of the liquidwith the resist and also, for a given liquid volume, on the height ofthe resist barrier. A possible solution to reduce the wetting mayaccordingly be to increase the height of the resist barrier. However, athick resist layer on top of other display elements, such as the pixelelectrode, negatively affects the display performance as higher drivingvoltages are required and the electrode becomes less transparent whichcan lead to a reduced front of screen performance in reflectivedisplays. Further, the mechanical stability decreases with a higheraspect ratio of the resist structures.

Another option to increase the contact angle by a surface treatment,e.g. a CF₄, or CHF₃ plasma would increase the contact angle of theliquid with the substrate. Such a treatment, however, appears to beunfavorable for the transistor characteristics.

Hence, an improved structure for a semiconductor arrangement and methodof manufacturing a semiconductor arrangement would be advantageous andin particular an improved structure that reduces wettability for asolution containing a semiconductor would be advantageous.

Accordingly, the Invention preferably seeks to mitigate, alleviate oreliminate one or more of the above mentioned disadvantages singly or inany combination.

According to a first aspect of the invention, there is provided astructure for a semiconductor arrangement, comprising: a resiststructure coupled to a substrate; the resist structure comprising adepression for depositing of a solution containing a semiconductor or aprecursor thereof, and a trough aligning at least part of an edge of thedepression and separated from the depression by a protrusion.

The invention allows for the solution containing a soluble semiconductor(or a precursor thereof) to have an increased volume without extendingbeyond the trough. The contact angle relevant to wettability of thesolution containing the semiconductor may be the contact angle betweenthe surface of the solution containing the semiconductor and the surfaceof a wall of the trough rather than of the general surface plane of theresist structure. Accordingly, by forming the side of the trough toprovide a higher angle with respect to the surface of the solutioncontaining the organic semiconductor than the surface next to thedepression an increased contact angle and thus reduced wettability maybe achieved.

The resist structure may enlarge the maximum contact angle (which is ameasure for the wettability) with respect to the general substratesurface plane from typical values around for example 10-20° to about 90°or even more.

The invention allows for improved definition of the area to be coveredby the solution containing the organic semiconductor and for asubstantially increased solution containing the organic semiconductorvolume to be deposited for each depression.

The resist structure may preferably have depth of between 0.5 and 15 μm,and in particular a depth of between 2 and 5 μm has been found toprovide particular advantageous results. The depression may similarlypreferably have a depth of between 0.5 and 15 μm and in particular adepth of between 2 and 5 μm as been found to provide particularadvantageous results. The trough width is not critical but may forexample be in the region of 2 to 15 μm. The distance between thedepression and the first side of the trough is preferably also between 2and 15 μm. Typically the concentration of the semiconductor in thesolution is within the range of 0.1% to 10% and often in the order of1%.

Different shapes of the protrusion may be used, including a rectangularcross-section, a truncated cone, an inverse truncated cone (e.g. withthe wall having at the bottom a width that is smaller than at the top),or a side wall with a rounded top.

The resist structure is coupled to the substrate but is not necessarilyin direct contact with the substrate. Thus, other layers may be situatedbetween the substrate and the resist structure. The resist structure mayspecifically be formed in a layer, which is part of a functional layerof the semiconductor arrangement, or in a layer used in themanufacturing process. For example, the resist structure may be formedin a gate dielectricum layer, insulator layer between interconnect linesor a photo resist layer used for patterning of underlying layers.

The resist structure can be made in various ways includingphotolithography, embossing, microcontact printing and injectionmolding.

According to a feature of the invention, the resist structure is formedin a single layer of the semiconductor arrangement.

According to another feature of the invention, the trough substantiallysurrounds the depression. This provides improved wettability in alldirections.

According to another feature of the invention, the semiconductor is anorganic semiconductor.

According to another feature of the invention, a width of an end of theprotrusion distal from the substrate is larger than a width of an end ofthe protrusion proximal to the substrate. A protrusion of increasingwidth may provide for an increasing contact angle, which may extendbeyond 90°.

According to another feature of the invention, a width of an end of theprotrusion proximal to the substrate is larger than a width of an end ofthe protrusion distal from the substrate. A protrusion of decreasingwidth may achieve increased mechanical robustness of the protrusion andmay allow a desired reduced maximum contact angle to be achieved.

According to another feature of the invention, the protrusion has asubstantially frusto-conical cross section. This allows for a protrusionwhich has suitable mechanical and resist properties and which issuitable for a low complexity manufacturing process.

According to another feature of the invention, the resist structure isformed by a polymer layer. A polymer material has properties which areparticularly suitable for formation of a resist structure for asemiconductor arrangement and especially when an organic semiconductoris used.

According to another feature of the invention a cross section of thedepression substantially perpendicular to the direction of depressioncomprises rounded corners. The edge of the depression when viewed fromabove the substrate may preferably be smooth and without sharp edges,corners or discontinuities. This allows for an improved contact betweenthe solution containing the semiconductor and the resist and improveswettability.

According to another feature of the invention, a cross section of thedepression substantially perpendicular to the direction of depression issubstantially rectangular. The edge of the depression when viewed fromabove the substrate is preferably substantially rectangular butpreferably has rounded corners. This allows for a particularly suitableshape for depositing semiconductors for example for forming of FieldEffect Transistors.

According to another feature of the invention, a depth of the trough issubstantially the same as a depth of the depression. This allows for asimple manufacturing process wherein the trough and the depression maybe formed by the same operation using the same parameters. Specifically,the depth of both the depression and the trough may be equal to thedepth of the resist layer thereby allowing the depression and trough tobe formed by removal of the entire layer at the appropriate locations,for example by an etching technique.

According to another feature of the invention, the depression comprisesa semiconductor forming the active layer of a field effect transistor.Hence, the invention allows for a structure which is suitable foraccurate depositing of a semiconductor for a field effect transistor. Asimple manufacturing process may be achieved.

According to another feature of the invention, the field effecttransistor comprises a source and drain having a plurality ofinterdigitated electrodes and a gate extending across the plurality ofinterdigitated electrodes.

According to another feature of the invention, the depression extendsbeyond the gate in a direction substantially perpendicular to thelongitudinal direction of the interdigitated fingers. This provides forparticularly suitable transistor parameters and allows for thesemiconductor to, in the substantially perpendicular direction, extendbeyond the channel areas defined by the conductors of the field effecttransistor. This mitigates or prevents that a small deviation in theoverlay between the cavity and the underlying layers results in avariation of parasitic capacitances. This is particularly advantageousif the transistor is part of a display, where a variation in overlap mayhave a negative effect on the display quality.

According to another feature of the invention, the depression does notextend beyond the gate in a direction substantially aligned with thelongitudinal direction of the interdigitated fingers. This provides forparticularly suitable transistor parameters and prevents thesemiconductor extending, in the substantially aligned direction, beyondthe channel areas defined by the conductors of the field effecttransistor. This is particularly important for normally on transistors.For normally on transistors, the organic semiconductor can already carrycharge carriers from source to drain and/or vice versa when the appliedvoltage on the gate-electrode is zero. An extension beyond the gateleads to a leakage path between source and drain electrode.

The structure may preferably be used in an integrated circuit, a (thinfilm) transistor active matrix display, an active matrix backplane or anelectroluminescent device.

According to a second aspect of the invention, there is provided amethod of manufacturing a semiconductor arrangement; the methodcomprising the steps of: providing a substrate; applying a resiststructure coupled to the substrate; the resist structure comprising adepression for depositing of a solution containing a semiconductor or aprecursor thereof, and a trough aligning at least part of an edge of thedepression and separated from the depression by a protrusion; anddepositing the solution in the depression.

Preferably, the depositing of the solution containing the organicsemiconductor is by a printing process such as micro contact printing,micromoulding in capillaries (MIMIC), drop-on-demand ink jet printing(bubble jet or piezo-electric), continuous ink-jet printing, screenprinting or flexographic printing.

These and other aspects, features and advantages of the invention willbe apparent from and elucidated with reference to the embodiment(s)described hereinafter.

An embodiment of the invention will be described, by way of exampleonly, with reference to the drawings, in which

FIG. 1 illustrates a cross section of a well of a resist structure inaccordance with prior art;

FIG. 2 illustrates a cross section of a well of a resist structure inaccordance with prior art;

FIG. 3 illustrates a cross section of a resist structure in accordancewith an embodiment of the invention;

FIG. 4 illustrates examples of cross-sections of a protrusion inaccordance with embodiments of the invention;

FIG. 5 illustrates a top view of a resist structure in accordance withan embodiment of the invention;

FIG. 6 illustrates a cross section of a bottom gate structure FETcomprising a structure in accordance with an embodiment of theinvention; and

FIG. 7 illustrates a top view of the electrode layers of the FET of FIG.6.

The following description focuses on an embodiment of the inventionapplicable to an organic semiconductor structure. However, it will beappreciated that the invention is not limited to this application butmay be applied to many other semiconductor arrangements.

Semiconductor arrangements and structures used for example for formingfield effect transistors in integrated circuits or semiconductor baseddisplays (e.g. thin film transistor (TFT) displays) are typically formedby depositing and patterning different layers on a substrate. Awell-known and cheap method of depositing suitable materials is spincoating. This is typically followed by a patterning process, which mayfor example comprise a photolithographic exposure of a photoresistfollowed by an etching step as is well known in the art.

However, in recent years other techniques have emerged for manufacturingsemiconductor arrangements. A very advantageous technique is directprinting of e.g. a solution containing the semiconductor or a precursorthereof on a resist layer. For example, ink jet printing allows for adroplet of solution containing the semiconductor to be deposited at adesired location. As the droplets can be very small and can bepositioned accurately, it is possible to provide the desired patterndirectly by the printing process without requiring a separate patterningstep.

The semiconductor material may be of different constitution, includinginorganic semiconductors such as CdSe (provided as precursor),nanomaterial-type semiconductors, in the form of particles or in theform of nanotubes or nanowires and organic semiconductors.

In order to facilitate and assist the accurate depositing of a solutioncontaining the semiconductor, the resist structure preferably comprisesa well for each droplet deposited by the printing process. For example,if a TFT display is manufactured, a matrix of evenly distributed pixelFETs is formed over the display area. Each droplet of solutioncontaining the semiconductor may be deposited so as to form the channelof the pixel FET. Hence, before the ink jet printing of the solutioncontaining the semiconductor, the resist is provided with an evenlydistributed array of wells having a size corresponding to the desiredsemiconductor size. Typically, such wells are rectangular and may forexample have a length of 400 μm, a width of 50 μm and a depth of 5 μm.In other embodiments, the well or depression may of course have otherdimensions depending on the requirements of the specific embodiment. Insome embodiments, a plurality of droplets may be deposited in a singledepression.

FIG. 3 illustrates a cross section of a resist structure in accordancewith an embodiment of the invention The resist structure is coupled tothe substrate on which the semiconductor arrangement is formed eitherdirectly or fully or partially through intervening layers.

A depression 301 for depositing of a solution containing thesemiconductor is formed in a resist 303. In addition, a trough 305aligning at least part of an edge of the depression 301 is formed in theresist 303. The trough 305 is separated from the depression 301 by aprotrusion 307.

During printing, a droplet 309 of solution containing the semiconductoris dropped in the depression 301. The surface of the droplet will forman angle θ with the plane of the resist. In the prior art resiststructure, wetting will occur when θ exceeds a given value whichtypically is in the area of 10-20°.

However, as illustrated in FIG. 3, when the droplet 309 comes intocontact with the trough 305 the relevant contact angle is no longer thatof the surface of the droplet 309 and the plane of the resist Rather,the relevant contact angle for the wetting effect is that between thesurface of the droplet 309 and the surface in which it is in contact,which in this case is the side 311 of the trough 305. Thus the relevantcontact angle for the continued wetting of the solution containing thesemiconductor is that of φ. As illustrated in FIG. 3 this angle is muchlower than θ. In the shown example, the θ is approximately 60° (whichwould cause further wetting), whereas the angle φ is approximately −30°.Thus in the shown example where the side wall of the trough issubstantially perpendicular to the plane of the resist 303, the angle θbetween the droplet surface and the plane of the substrate at whichwetting occurs is approximately 90° higher than without the presence ofthe trough. Thus, the function of the trough line is to pin the liquid.

Hence in accordance with the shown embodiment, a much improved wettingperformance of the resist structure is achieved by the provision of atrough aligning the edge of the depression. The maximum contact anglemay thus be increased substantially. This allows, for example, for amuch increased amount of semiconductor material to be provided within agiven area. This provides the advantage of a self-aligned process whichprevents wetting of the resist area outside of the depression, applyinga thicker semi-conductor layer inside the depression and having a morerobust and reproducible process.

It should be noted that the above described pinning process assumes thatthe contact angle between the solution containing the semiconductor andthe resist surface is the predominant effect controlling the wettingcharacteristics. It will be appreciated by the person skilled in the artthat other effects, such as Marangoni forces, due to a gradient insurface tension, may have an impact on the wetting of the solutioncontaining the organic semiconductor and that therefore the obtainedimprovement may be less than described in the given example.

It should be noted that FIG. 3 illustrates the structure for a singlesemiconductor deposit e.g. corresponding to a single transistor.Specifically, the transistor may be a pixel transistor for a display. Ina semiconductor arrangement comprising a plurality of transistors, othertroughs and depressions will be formed in the resist structure. Forexample, for a matrix display, other transistors will be formed at agiven distance L from the shown transistor (typically in twoperpendicular directions). Thus other depressions may be formed in theresist layer at a maximum distance L of at most the pixel dimension,which will typically be 100-1000 μm. The transistor for the adjacentpixel will be formed using this depression.

For some purposes, it may be advantageous to decrease the height of thebase resist layer to that of the depression at a much smaller distance.For example, the trough may be formed by the protrusion and an outerwall which is of the same magnitude or even smaller than the protrusion.In other words, the resist layer may in some embodiments be removed fromareas where it is not used to form depressions or troughs.

In the preferred embodiment, the depression and the trough are formed inthe same layer and have the same depth. This allows for a simplemanufacturing process where no differentiation is required between thetrough and the depression. Specifically, the depth of the trough and thedepression is preferably equal to the depth of the layer, such that thedepression and the layer can be performed simply by removing the entirelayer.

The resist layer preferably has a thickness in the order of 1-5 μm.Preferably the resist area covers the entire area of the semiconductorarrangement but in some embodiments the resist is absent outside thearea wherein the depressions are formed.

The pattern of the resist structure can be formed using differenttechniques known to the person skilled in the art includingphotolithography, embossing, microcontact printing, or injectionmolding.

The resist structure is preferably made of a polymer material and thesolution containing the organic semiconductor is preferably an organicsemiconductors including, the polyphenylenevinylenes, thepolythienylene-vinylenes, polyfluorenes, blends of carrier materials andoligomers, (particularly pentacene), polyarylamines, polythiophenes, andthe like, copolymers of oligomers and non-semiconductung monomers. Theseorganic semiconductors may include any side-chains (alkyl-, alkoxygroupsin particular but not exclusively) as known to the skilled person in theart. The resist layer may furthermore have a second purpose. Forexample, the resist layer may also be used as an isolator between e.g.the second and third metal layer, which is patterned with an additionalmask. In view of underlying layers, use of wet-chemical etching ispreferred. The dielectric layer is preferred above the photo resist, inorder to avoid that the photo resist has an undesired impact on thestability of the organic semiconductor.

The deposition of the solution containing the semiconductor ispreferably by a printing process but it is within the contemplation ofthe invention that any suitable process may be used. The printing mayfor example be by drop-on-demand ink jet printing (which may e.g. bebubble jet or piezo electric printing), continuous ink-jet printing,screen printing, flexographic printing, micro contact printing orMicromoulding in capillaries (MIMIC).

The cross-sectional shape or dimensions of the protrusion may bedetermined by the person skilled in the art to suit the specificapplication. FIG. 4 illustrates examples of cross-sections of aprotrusion in accordance with an embodiment of the invention.

As illustrated, the cross section may for example be rectangular, haverounded edges or be frusto-conical. Especially, the frusto conical shapeis advantageous as it allows for a simple structure, which allows for anoptimization of the maximum contact angle.

In some embodiments, a width of an end of the protrusion distal from thesubstrate is larger than a width of an end of the protrusion proximal tothe substrate. For example, the width of the protrusion illustrated inFIG. 4 may be larger at the top of the protrusion than at the bottom.

Such an inverse truncated cone shape of the intermediate wall isparticularly advantageous as it allows that the printed liquid (droplet)has a contact angle with respect to the substrate of more than 90°; i.e.with a relatively thin layer for the resist structure, it is possible toprovide a large amount of material.

In other embodiments, a width of an end of the protrusion proximal tothe substrate is larger than a width of an end of the protrusion distalfrom the substrate. For example, the width of the protrusion illustratedin FIG. 4 may be smaller at the top of the protrusion than at thebottom. This allows for smaller maximum contact angles but may provide amore mechanically robust structure.

FIG. 5 illustrates a top view of a resist structure in accordance withan embodiment of the invention. FIG. 5 corresponds to a top view of theresist structure of FIG. 3.

As shown in FIG. 5, the trough 305 preferably substantially surroundsthe depression. Thus, the trough preferably restricts the flow of adroplet in all directions along the plane of the resist layer.

Furthermore, as illustrated, the preferred shape of the depressioncorresponds to a substantially rectangular shape wherein the corners arerounded. Thus, in the preferred embodiment, no discontinuities or sharpcorners exist in the edge of the depression in the directionsubstantially perpendicular to the direction of depression, i.e. in theplane of the resist layer. This allows for an improved wettingperformance as thus reduces excess liquid in specific positions alongthe edge.

The resist structure and solution containing the semiconductor is in thepreferred embodiment part of a field effect transistor (FET) structure.Thus the resist structure is used in facilitating the formation of oneor more FETs.

Generally, a FET with an organic semiconductor can have two structures:a bottom-gate structure or a top-gate structure. FIG. 6 illustrates across section of a bottom gate structure FET comprising a structure inaccordance with an embodiment of the invention.

The FET comprises three electrodes: source 601, drain 603 and gate 605.The source and drain electrodes 601, 603 are present in one electricallyconducting layer, the gate: electrode 605 in another electricallyconducting layer. The organic semiconductor 309 is in contact with thesource 601 and drain 603 electrode, and forms the channel between theseelectrodes. The liquid containing the semiconductor 309 is separatedfrom the gate electrode 605 through a gate-dielectricum 607 (aperpendicular projection of the gate electrode onto the organicsemiconductor overlapping with the channel). In the bottom-gatestructure, the organic semiconductor may be provided as the last layer.

FIG. 6 illustrates the FET structure prior to drying which willtypically evaporate the solvent and leave the dry semiconducting layerto be contained within the depression.

It is preferred that the source and drain electrodes 601, 603 areprovided as a pair of interdigitated electrodes. FIG. 7 illustrates atop view of the electrode layers of the FET of FIG. 6.

As shown, the source and drain electrodes 601, 603 have fingers that areoriented substantially in parallel and which extend in a first direction701. The gate is positioned such that its perpendicular projectionsoverlap the fingers, but does not overlap the ends of the electrodefingers. It extends thus between a first and a second limit in the saida first direction 701. Preferably, the depression does not extend beyondthe projected edges of the gate-electrode in the first direction 701.Thus, the depression does not extend beyond the gate in a directionsubstantially aligned with the longitudinal direction 701 of theinterdigitated fingers.

This limitation is particularly advantageous for transistors with anormally on semiconductor material. In that case, the organicsemiconductor can carry charge carriers from source to drain and/or viceversa when the applied voltage on the gate-electrode is zero or higher.An extension beyond the gate will lead to a leakage path between sourceand drain electrode, since the transport of charge carriers cannot beprevented by a gate voltage if no gate is overlapping this area.

Furthermore, the projection of the gate 605 extends in a seconddirection 703 (which is generally substantially perpendicular to thefirst direction) and overlaps the fingers of the source- and drainelectrodes 601, 603 in this direction. In the preferred embodiment, thedepression preferably extends beyond the projected edges of thegate-electrode 605 in the second direction 703. Thus, the depressionpreferably extends beyond the gate 605 in a direction 703 substantiallyperpendicular to the longitudinal direction of the interdigitatedfingers.

By allowing the depression to overlap the gate in the second direction,it is prevented or mitigated that a small deviation in the overlaybetween the depression and the underlying layers has negative impact onthe transistor characteristics.

Suitable electrically conducting materials for forming the source, drainand gate electrodes include gold, paladium, platinum and other (noble)metals, oxidic conductors, such as ITO, polymeric conductors such aspolyaniline and polyethylenedioxythiophene (PEDOT), particularly incombination with a polyacid. For n-type semiconductor it is possible touse metals with lower work function besides the metals already mentionedfor p-type semiconductors.

Suitable gate dielectrica include all kind of organic insulators, and inprinciple also inorganic insulators.

In the preferred embodiment, the semiconductor arrangement is part of anintegrated circuit or a display or electroluminescent device.

Thus preferably, a multitude of FETs are formed using the describedstructure. Specifically, the FETs may be used in a display, for instanceas pixel transistors in a display with an electrophoreticelectro-optical layer.

The invention can be implemented in any suitable form and using anysuitable methods, processes and materials. The elements and componentsof an embodiment of the invention may be physically, functionally andlogically implemented in any suitable way. Indeed the functionality maybe implemented in a single unit, in a plurality of units or as part ofother functional units. As such, the invention may be implemented in asingle unit or may be physically and functionally distributed betweendifferent units.

Although the present invention has been described in connection with thepreferred embodiment, it is not intended to be limited to the specificform set forth herein. Rather, the scope of the present invention islimited only by the accompanying claims. In the claims, the termcomprising does not exclude the presence of other elements or steps.Furthermore, although individually listed, a plurality of means,elements or method steps may be implemented by e.g. a single unit orprocessor. Additionally, although individual features may be included indifferent claims, these may possibly be advantageously combined, and theinclusion in different claims does not imply that a combination offeatures is no feasible and/or advantageous. In addition, singularreferences do not exclude a plurality. Thus references to “a”, “an”,“first”, “second” etc. do not preclude a plurality.

1. A structure for a semiconductor arrangement; comprising a resiststructure coupled to a substrate; the resist structure comprising: adepression for depositing of a solution containing a semiconductor or aprecursor thereof and a trough aligning at least part of an edge of thedepression and separated from the depression by a protrusion.
 2. Astructure as claimed in claim 1 wherein the resist structure is formedin a single layer of the semiconductor arrangement.
 3. A structure asclaimed in claim 1 wherein the trough substantially surrounds thedepression.
 4. A structure as claimed in claim 1 wherein thesemiconductor is an organic semiconductor.
 5. A structure as claimed inclaim 1 wherein a width of an end of the protrusion distal from thesubstrate is larger than a width of an end of the protrusion proximal tothe substrate.
 6. A structure as claimed in claim 1 wherein a width ofan end of the protrusion proximal to the substrate is larger than awidth of an end of the protrusion distal from the substrate.
 7. Astructure as claimed in claim 5, wherein the protrusion has asubstantially frusto-conical cross section.
 8. A structure as claimed inclaim 1 wherein the resist structure is formed by a polymer layer.
 9. Astructure as claimed in claim 1 wherein a cross section of thedepression substantially perpendicular to the direction of depressioncomprises rounded corners.
 10. A structure as claimed in claim 1 whereina cross section of the depression substantially perpendicular to thedirection of depression is substantially rectangular.
 11. A structure asclaimed in claim 1 wherein a depth of the trough is substantially thesame as a depth of the depression.
 12. A structure as claimed in claim 1wherein the depression comprises a semiconductor forming an active layerof a field effect transistor.
 13. A structure as claimed in claim 12wherein the field effect transistor comprises a source and drain havinga plurality of interdigitated electrodes and a gate extending across theplurality of interdigitated electrodes.
 14. A structure as claimed inclaim 13 wherein the depression extends beyond the gate in a directionsubstantially perpendicular to the longitudinal direction of theinterdigitated fingers.
 15. A structure as claimed in claim 14 whereinthe depression does not extend beyond the gate in a directionsubstantially aligned with the longitudinal direction of theinterdigitated fingers.
 16. An electronic device comprising the resiststructure claim
 1. 17. An electronic device, comprising a resiststructure coupled to a substrate; the resist structure comprising: adepression for depositing of a solution containing a semiconductor or aprecursor thereof and a trough aligning at least part of an edge of thedepression and separated from the depression by a protrusion, whereinthe depression comprises a semiconductor forming an active layer of afield effect transistor.
 18. An electronic device comprising a resiststructure coupled to a substrate; the resist structure comprising: adepression for depositing of a solution containing a semiconductor or aprecursor thereof and a trough aligning at least part of an edge of thedepression and separated from the depression by a protrusion, providedwith an active matrix backplane or active matrix display comprising, astructure for a semiconductor arrangement; comprising a resist structurecoupled to a substrate; the resist structure comprising: a depressionfor depositing of a solution containing a semiconductor or a precursorthereof and a trough aligning at least part of an edge of the depressionand separated from the depression by a protrusion, wherein thedepression comprises a semiconductor forming an active layer of a fieldeffect transistor.
 19. An electroluminescent device comprising thestructure of claim
 12. 20. A method of manufacturing a semiconductorarrangement; the method comprising the steps of: providing a substrate;applying a resist structure coupled to the substrate; the resiststructure comprising a depression for depositing of a solutioncontaining a semiconductor or a precursor thereof and a trough aligningat least part of an edge of the depression and separated from thedepression by a protrusion; and depositing the solution containing thesemiconductor in the depression.
 21. A method as claimed in claim 20wherein the depositing of the solution is by a printing process.
 22. Amethod as claimed in claim 21 wherein the depositing of the solution isby an ink jet printing process.